Flame retardant for textiles

ABSTRACT

Aqueous solutions of dimethylol dicyandiamide and phosphoric acid useful as durable finishes on cellulosic textile materials to impart flame retardance and the cellulosic textile materials treated therewith.

United States Patent [72] Inventors Samuel James O'Brien Dunellen;Robert George Weyker, North Plainfleld, both 01 NJ. 21 Appl. No. 866,402[22] Filed Oct. 14, 1969 [45] Patented Dec. 7, 1971 [73] AssigneeAmerican Cyanamid Company Stamford, Conn.

[54] FLAME RETARDANT FOR TEXTILES 5 Claims, No Drawings [52] US. Cl117/137, 1 17/ 143 A [51] Int. Cl C09k 3/28, D06m 13/26 [50] Field ofSearch 117/136, 143,137;8/116,l16.2;252/8.1;106/15 F1 [56] ReferencesCited UNITED STATES PATENTS 2,421,218 5/1947 Pollack 117/136X 2,519,3888/1950 7 Loukomsky et a1. 117/137 X 2,530,261 11/1950 Morton et a1.117/137 X 2,784,159 3/1957 Fluck et al.. 117/137X 2,917,408 12/1959Goldslein et a1.. 117/137 X 3,105,773 10/1963 Frank et al 117/723,159,503 12/1964 Goldstein et al. 1 17/137 3,253,881 5/1966 Donahue...106/15 X 3,459,588 8/1969 Davis 117/143 X FOREIGN PATENTS 476,04311/1937 Great Britain 1 17/137 1,114,181 4/1962 Germany 117/137 OTHERREFERENCES O Brien, Textile Research Journal, Cyanamide...Cotton, PPs256-266, 1 968 March). Primary Examiner-William D. Martin AssistantExaminer-Harry J. Gwinnell AttorneyCharles J. Fickey FLAME RETARDANT FORTEXTILES This invention relates to an aqueous flame-retardant finish forcellulosic textile materials. More particularly, it relates to (1)aqueous solutions of dimethylol dicyandiamide and phosphoric acid, (2)to their use as a durable finish on cellulosic textile materials toimpart flame retardancy, and (3) to the treated cellulosic textilematerials.

The use of monomethylol dicyandiamide in flame-retardant finishes forcellulosic textile materials is well known. For example, U.S. Pat. No.2,519,388, discloses its use in combination with phosphoric acid andmethylol urea or a methylol melamine. The coapplication with anaminoplast resin, such as a methylol melamine, is necessary to obtaingood wash durability of the flame-retardant finish. Also, monomethyloldicyandiamide is costly to manufacture. Because of insolubility inwater, monomethylol dicyandiamide must be isolated and the isolationsteps add considerably to the cost of the product, thus resulting in aprice deterrent to the customer.

it is therefore an object of this invention to provide a flameretardantfinish for cellulosic textile materials which is economical and durableto laundering.

This and other objects of the invention will become apparent as thedescription thereof proceeds.

it has now been discovered that a dimethylol dicyandiamide andphosphoric acid flame-retardant system does not require thecoapplication of an aminoplast resin, such as a methylol melamine, inorder to obtain durability of the finish on cellulosic textilematerials. Furthermore, dimethylol dicyandiamide is water-soluble andcan be manufactured and used in the flame-retardant finish withisolation. An added advantage of the flame-retardant finish of thisinvention is the relatively small strength loss sustained by the textilematerials when reacted with the finish.

The dimethylol dicyandimide can be prepared by heating a mixture ofdicyandiamide with two-mole equivalents of aqueous formaldehyde(fonnalin) to a temperature of about 70 C. Heating of the clear solutionis continued for about l hour. The resulting aqueous solution ofdimethylol dicyandiamide contains 50-60 percent solids and it can beused in the process of this invention.

The phosphoric acid used in the process of this invention is preferablyortho-phosphoric acid (H PO,). The commercial 85 percent acid isconveniently employed.

The dimethylol dicyandiamide-phosphoric acid finish can be convenientlyapplied to textile materials as an aqueous solution. The textilematerial can be treated by padding, spraying, dipping etc. Thecellulosic textile material should contain at least 50 percentcellulosic fibers. By the term cellulosic fibers" is meant such fibersas cotton, regenerated cellulose (rayon), linen, jute, etc. Blends ofcellulosic fibers with other cellulosic fibers or with noncellulosicfibers, both natural and synthetic, such as silk, wool, polyamide,polyesters, polyacrylonitrile, e.g., may be used.

The amount of the dimethylol dicyandiamide-phosphoric acid finishapplied to the textile material should be between 30 and 45 percentbased on the weight of the textile material. The amount of dimethyloldicyandiamide in the finish should be between 15 and 40 percent,preferably between 20 and 30 percent, based on the weight of the textilematerial, and the amount of phosphoric acid should be between 5 and 20percent, preferably between 7.5 and percent, based on the weight of thetextile material. Furthermore, the amount of dimethylol dicyandiamideand phosphoric acid in the aqueous solution will be adjusted to providethe amount of pickup on the textile material, as pointed out above, andwill depend on the method of application. It is within the skill of theart to determine the amounts required in the solution.

The treated textile material is dried by any convenient means, as in anoven at from about 200 to 250 F., preferably 225 F., and is then heatedat an elevated temperature to effect a cure of the finish on the textilematerial. A temperature between 225 F. and 400 F., preferably between250 F. and 350 F., is recommended for the curing operation. This timerequired is between about 1 and 5 minutes depending on the temperatureused and the weight of the fabric. If desired, the drying and curingoperation can be done in one step.

The following specific examples are set forth to illustrate someembodiments of the invention and are not intended to be limitative.

EXAMPLE I Preparation of Dimethylol Dicyandiamide A mixture of 1,180 g.(14 moles) dicyandiamide and 2,330 g. of 35 percent aqueous formaldehyde(28 moles) was heated slowly to C., whereupon the mixture became clear.Heating was then continued at C. for one hour. The product containedabout 55 percent solids.

EXAMPLES ll-XXlV Twenty-three aqueous pad baths were prepared containingthe percentage amounts on a solid basis of dimethylol dicyandiamide(DD), product of example i, and orthophosphoric acid (11 1 0,) shown intable I.

The pad baths were applied to X80 percale by a standard paddingprocedure obtaining a 82 percent wet pickup. The padded fabrics weredried at 225 F. for 2 minutes and then heated at 325 F. for 3 minutes.

The durability of the fire-retardant finish to laundering was determinedby repeatedly washing the fabric in an automatic washing machine usingwater at C. and a commercial detergent. After each washing operation,the flame resistance of the fabrics was determined by a vertical flametest according to Standard Test Method AATCC 34-1966. The washings andflame testings were continued as long as the char length of the burntfabric was less than 6 inches. The limit of wash durability was reachedwhen the char length was 6 inches.

The amounts of dimethylol dicyandiamide and phosphoric acid on thetextile material and the durability of each finish to laundering areshown in table I.

TABLE I Pad bath compo- Trested textile material, Durability sition,percent percent OWF o1 finish Example No. of number DD HsPO DD H,POwashes 3O 15. 3 24. 6 12. 5 ll We claim:

1. A process for producing a durable flame-retardant finish oncellulosic textile materials comprising the steps of:

a. forming a coated cellulosic textile by applying a flame-retardantcomposition consisting essentially of an aqueous solution of dimethyloldicyandiamide and phosphoric acid to said cellulosic textile materials,wherein the amount of dimethylol dicyandiamide and phosphoric acid arein the ranges of 15 to 40 percent and 5 to 20 percent, respectively,based on the weight of the textile; and

b. heating the coated textile to dry and cure the finish thereon.

2. The process of claim 1 wherein said coated textile is subtemperatureof from about 200 to 250 F. and subsequently sequently heated to atemperature from about 225 to 400 F. heated to from 250 to 350 F. tocure said finish.

3, The ro es of l im 2 h r i id temperature i f 5. A cellulosic textilematerial obtained by the process of about 250 to 350 F. claim 1.

4. The process of claim 1 wherein said textile is dried at a 5 t s sUNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 25,753 Date D mber 71 1971 Inventor(s) Samuel James O'Brien and RobertGeorge Weyker It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 52, "with" should read without Column 1, line 36,"dicyandimide" should read dicyandiamide Column 1, line 75, "This"should read The Signed and sealed this 9th day of May 1972.

(SEAL) Attest:

EDWARD M.FLETGHER, JR. ROBERT GOTTSCHALK Atteating Officer Commissionerof Patents RM PC4050 USCOMM-DC 60S76-P59 U-SA GOVERNMINT PRINTINGOFFICE: II" 0-8..3!

2. The process of claim 1 wherein said coated textile is subsequentlyheated to a temperature from about 225* to 400* F.
 3. The process ofclaim 2 wherein said temperature is from about 250* to 350* F.
 4. Theprocess of claim 1 wherein said textile is dried at a temperature offrom about 200* to 250* F. and subsequently heated to from 250* to 350*F. to cure said finish.
 5. A cellulosic textile material obtained by theprocess of claim 1.